Day 4: Class vs. Instance

https://www.hackerrank.com/challenges/30-class-vs-instance/problem

<?php
class Person{
	public $age;
    public function __construct($initialAge){
      // Add some more code to run some checks on initialAge
      if($initialAge<0){
          echo "Age is not valid, setting age to 0.\n";
          $initialAge = 0;
      }
      $this->age = $initialAge;

	}
    public  function amIOld(){
        // Do some computations in here and print out the correct statement to the console 
        if($this->age<13){
            echo "You are young.\n";
        } else if($this->age>= 13 && $this->age<18){
            echo "You are a teenager.\n";
        } else {
            echo "You are old.\n";
        }

	}
    public  function yearPasses(){
        // Increment the age of the person in here
        $this->age++;
    }
}